What is DVB-S and DVB-S2 and the difference?

DVB-S(Digital Video Broadcasting – Satellite) is the original Digital Video Broadcasting forward error coding and modulation standard for satellite television. The first application was commercially available in France via Canal+, enabling digitally broadcast, satellite-delivered television to the public.

It is used via satellites serving every continent of the world. DVB-S is used in both MCPC and SCPC modes for broadcast network feeds, as well as for direct broadcast satellite services like Sky Digital (UK) via Astra in Europe, Dish Network and Globecast in the U.S. and Bell TV in Canada.

While the actual DVB-S standard only specifies physical link characteristics and framing, the overlaid transport stream delivered by DVB-S is mandated as MPEG-2, known as MPEG transport stream (MPEG-TS).

Some amateur television repeaters also use this mode in the 1.2 GHz amateur band.

DVB-S2 (Digital Video Broadcasting – Satellite – Second Generation) is designed as a substitute for the DVB-S standard. It is based on DVB-S and the DVB-DSNG (Digital Satellite News Gathering) standard, used by mobile units for sending external footage back to television stations. DVB-S2 is envisaged for broadcast services including standard and HDTV, interactive services including Internet access, and (professional) data content distribution. The development of DVB-S2 coincided with the introduction of HDTV and H.264 (MPEG-4 AVC) video codecs.

Two new key features that were added compared to the DVB-S standard are:
* A powerful coding scheme based on a modern LDPC code.
* VCM (Variable Coding and Modulation) and ACM (Adaptive Coding and Modulation) modes, which allow optimizing bandwidth utilization by dynamically changing transmission parameters.

There are also other features, such as enhanced modulation schemes up to 32APSK, additional code rates, and the introduction of a generic transport mechanism for IP packet data including MPEG-4 audio�video streams, while supporting backward compatibility with existing MPEG-2 TS based transmission.

The standard document claims that the DVB-S2 performance gain over DVB-S is around 30% at the same satellite transponder bandwidth and emitted signal power. When the contribution of improvements in video compression is added, an (MPEG-4 AVC) HDTV service can now be delivered in the same capacity that supported an early DVB-S based MPEG-2 SDTV service only a decade before.